crosland



Jan. 31, E. M. CROSLAND AND oTHER HEAT'NG OPERATIONS OVEN FOR BAKING, DRYING',

5 Sheets-Sheet l Filxed Jan. 18. 1927 mi m; 9 /QQ/ Q.

Jan. 3l, 1928.

E. `M. CROSLAND OVEN`.FOR BAKING, DHYING, AND'OTHER HEATING OPERATIONSA Filed Jan. 18, 1927 5 sheets-'sheet 2 Jan. 31, 1928.

E. M. cRosLAND 2 OVEN FOR BAKING, DRYING, AND OTHER HEATING OPERATIONS Filed Jan.18, 1927 s sheets-sheet 3 3N @L o A5 loJ6 Z" Q r z2 @s -EE c5 ,Si

Jan. 3l, 1928;

i E. M. CROSLAND OVEN Fon BAKING, DRYING, ANDQTHER HEATING OPERATIONS File d Jan. 18. 192? 5 Sheets-Sheet '4 Jan. 3l, 192.8..

E. M. CROSLND ovEN FOR-BAKING, DRYING, AND OTHER HEATING OPERATIONS 5 Sheets-Sheet 5 www llllllilllillllllrll.

Patented Jan. 31, 1922?.`

EDWARD'MILNER CROSLAND, OF NEWTON-LE-WILLOVJS, ElGrIulhl'I).`

CiVIilN` FOR BAKING, DRYING, AND OTHER HEATING( OPERATIONS.

Application led January 18, `1927, Serial No. 161,772, and in Great Britain January 4, 1926.

The present invention relates to improvements in heating, drying or baking ovens and more particularly to ovens heated byy the combustion of gas and where the ma terial or goods to be baked are situated in multiple tiers, that is to say, they do not lie in any one horizontal plane but in tiers on different planes one above the other.

In niultipletier ovens considerable dilliculty has been experienced in heating the bottom of the oven, `as due to the natural tendency oit hot gases to rise, it results in the top of the oven soon becoming hotter than the bottom.

Further in suoli multiple tier ovens the space for the escapeor passage of the gases ot combustion and for the steam rising` trom the goodsv being heated is somewhat limited and in consequence ot this the rising heated gases and steam tend to escape with a considerable velocity causing draught to be set up` with a consequent,detrimental and uneven effect on the baking ot the goods.

lWith a view to avoiding these disadvantages and obtaining a greater eiiiciency of heating from the gas, according to the present invention the goods within the multiple tier oven are heated on both sides by means ofV radiators, that is tosay, there may be one more tier or row of radiators than tiers or rows of goods to be baked in tlieoven.

Further bythe present invention the radiators are connected togetherI so that gases ot combustion after passing along one radiator will pass to the radiator situated below this, whereupon the gases will travel along this lower radiator and then by a passage to a still lower radiator until the bottoni radiator is reached whereullion the gases pass into the waste liuc.

It will thus be seen that by separating` the gases ot combustion from the goods to be baked, and by causing the gases of combustion to travel downwardly, i. e. in the opposite direction to the normal flow hot gases-the gases ot combustion will be used to a greater extent involving less waste, in thatthe lower radiators will receive heat from the descending gases of combustion in addition to the heat generated by the burners situated in such lower radiators. Further, the heat radiated by the lower ra diators will assist in heating the whole of the oven as in the case of an oven heated directly by burners, in that the air within the oven and external ot the radiators will rise when heated towards the top of the oven. By the construction ot the present invention it `is found that after the oven has been heated tor some time it is possible to maintain the necessary temperature at the lower portion of the oven solely by the descending gases of combustion within the radiators thus dispensing with the `burners Figure l is a partial sectional longitudi` nal elevation of an oven, showing one portion only of the oven, the complete longitudiiial section of the oven being iliade up of a number of the sections of this ligure.

Figure 5 is an end cross section on the line 5-5 ot Fig. Il; i

Figure G is a similar end cross section on the line 6 6 of Figure 4.

Figure i is a part longitudinal section of a convenient form of burner.

The goods to be baked, heated, dried or otherwise treated in the oven, are passed into this at a point l upon a conveyor 2 moving continuously or step by step and passing through the oven in a number of tiers to leave it through the delivery opening' 3. The oven is divided longitudinally into a iulinbcr o 'l chauibers l, 5, G, through which the conveyor 2 guided by sprocket wheels 7, 8 or the like means. The partitions between these chambers are hollow, and are formed ot upper walls 9, and lower walls l() forming flues through which the heating gases can pass. It will thus be seen that the oven comprises the heating chambers A, B,

C, D, which define the goods chambers 4, 5,.

6 between them.

The products ot combustion from burners 1l arranged between the walls 9, l() pass along between these right along the oven in the upper tier heating the top of the biscuits or the like material on the conveyor 2. These gases then pass down a vertical Hue l2 and mingle with gases vfrom `burners 13 arranged in the next hollow partition wall to heat the lower l'ace of the conveyor 2;

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These gases then having passed substantially the full length of the oven pass down through the vertical flue 1st, and mingle witl the products oi combustionv from burners l5 in the next lower partition wall heating the underside oixthe conveyor 2, as it passes back along` the oven and so on, "for any desired number oi tiers.

ldlhen the gases of combustion have passed along the lowerinost or iloor partitions ofthe oventhey pass upwards through iiues l? to the lue lil forming the toprot the oven and, coinn'iunicatingV with a chimney 20. Naked burners 19 may be provided in the goods chamber (i adiacentthe outlet 3 Jfor tae purposevoi aiiording a final crusting` or LbrowninUa `on the bread oi biscuit if so desired. in the lower heating` eliamber if) formed by the partition 1G are likewise provided the burnersl 16X lor the purpose oit heating the lower surface oil the conveyor on itspassage through the `goods chamber 6.

lt is preferred to so arrange the construe* tion of the oven that the direction of: flow oil. the products' of combustion is reversed in stages' along'` the oven. Such a construction is sliownin Figs.V 2 and 3 which are dii'llerent ysectionstaken longitudinally or one and the same oven. lt 4will be'noted that the direction oi' flow et gases is 'from leftto right in each of ,the hea-ting chambers C, lia, and 'from 'right' to left in the heatingchambers DjA, `It will further be noted that the gases pass 'from the right hand end ot the 'Y chamber ri, to its le'iit end downwardly in a flue 122L andtlien to theright in the heatin chamberCa: or; from the left hand end oi the heating chamber i3a toward the right and downward in aflue 14a and then to the lett in the heating chamber D, lt will thus be seen thatthere are two independent heating currents oi' gas within the oven. it is preferredy to divide lthe oven longitudinally by partitions, furthermore, so that the gas arriving' in the right hand end of the heating chamber CZL in one compartment may be directed downwardly into the lower heating chamber Dap: while in another compartment they will be directed upwardly through aline 30 to the yright hand portion lil" olf a conduit which leads to the stack 2Gb: while the body of gases passing` upwardly in the flue 171" succeedto the conduit Ea and thence to the lstack 20a. The direction of the 4arrows indicates the direction oi i'low ot the hotfgases.V y Y I in the` modified `iorm otA construction shown in Figures i to (5 con'iparatively small radiators `are used along` the length the oven, each of these small radiators being' connected at its ends to a similar small radiator situated immediately below it by means of short,connecting` flues' 21, which allow the gases to iinally pass up the outer connecting lines 22 up into the chimney 23. By subdividingl the length oit the oven into such small sections ot radiators the control ot these is considerably assisted.

rllhe partition v-:alls 9 and. l0 in either case. may be ribbed as shown at (do: (Y, to increase the effective adiatingi suriacc. ln both cases it willbe sec-n that the products ot combustion are czinipletely removed Alrom all possible contact with the joods beingij balfed, and jturth r that the oren can be couirolleih so that the pr( lucts ot combustion travel in a downwards direction 'through the lower radiators whereby much heat as possible :an be alestra i i'rori the pas bei'ore il reaches the exit il ic to counteract the normal tendency et Jthe heated products ol combos tion to rise.

rihe presentii fenion may also be applied ii desired to ovens where the 4remis lo be treated remain stationary, and where the treatment involves cit-her heatingj baiting?Y or drying.

In certain cases it may be desirable to omit the walls 9, l0, as regards for instance` the top iiigg'ht only, so that the products of combustion alone; this top row not havingij far to travel will not have suol a great disturbing eli'ect on the biscuits or the like material passing?r below i hem.

A convenient Aform of burner comprises an outer tube havin` perforations or slots 2i in it along its lengpijth7 which tube extends transversely across the oven within the heat chamber within an enlarged cross section thereof by preference: within the outer burner tube Qi; is located an inner burner tube 25 which fed at the end with gasair mixture and is likewise provided with holes or slots 25K therein. rlhe holes slots or like pertorations Qfix, 25X are disposed in stap'- gered relation so that they do not coincide respectively7 and the gas .leaving` the lube 25 is forced to ilollow a circuiious path bol'ore it escapes :trom the per'oratious dif" iu [he outer 'tube 24, and thus an eliicienl mixing' aud dis tribution ot the ras is obtained. ,ho tubes 2d, Q5 are held i'ixedly with regard lo each other7 while their assembly may be swivcled about7 together with the burner body do, by means ol? the handle i?, by means olf r[ined bearings 28 located upon the lixed gas pipe connection and the nozzle 2).

l declare that what l claim is l` it multiple lier oven including a moving); conveyor and meansto `cuide said conveyor in said oven iu multiple (iight, and internally heated radiators forming' walls between the successive flight chambers7 sich o'l said walls being composed ot a, plurality ol' individual sections, said section walls tor the successive, flights being` connected together by lateral vertical conduits comprising inner and outer conduits the inner conduits serving` to lead the grasos downward from one section wall to a section wall beneath it and loo lll)

the outer conduits serving to lead the gases upwardfrom a lower section to the discharge flue.

2. A multiple tier oven including a moving conveyor and means to guide said conveyor in said oven in multiple flight, and internally heated radiators forming walls between the successive flight chambers, the radiators forming said walls being divided along substantially vertical planes into a plurality of sections, each of said sections having at one end thereof conduits to establish communication between certain of said radiators and the respective radiator immediately below, and at the othei` end with conduits establishing communication between said latter rediators and a radiator beneath the saine, so that in each of said ysections a iiow of gases of combustion occurs successively along an upper radiator, thence downward to a lower radiator and in the reverse direction along said lower radiator,

and then downward into a still lower radiator and return in the lirst direction, and means for withdrawing the combustion gases from the lowerinost radiator to a discharge iiue.

3. A multiple tier oven including a moving conveyor and means to guide said conveyor in said oven in multiple flight, and internally heated radiators forming the walls of' the successive flight chambers, saidradiators being divided substantiallyvon vertical planes into a plurality of sections, each of said sections being connected at the respective ends by a conduit structure having inner and outer passages, the inner passages serving for passing gases from an upper radiator to a lower radiator of the section, and said outer passage serving for passing the gases from a lower radiator' to the discharge flue.

ln witness whereof I have hereunto signed. my naine this 5th day of January, 1927.

EDWARD MILNER CRGSLAND. 

